TED Radio Hour - Life Stages of the Brain

Episode Date: October 13, 2023

Original broadcast date: March 5, 2021. In each stage of life, our brains morph and change. This hour, TED speakers explore pivotal chapters where the brain can either flourish or decline – and what control we might have over brain health. Guests include neuroscientists Kimberly Noble, Adriana Galván, Sandrine Thuret, and Lisa Mosconi.TED Radio Hour+ subscribers now get access to bonus episodes, with more ideas from TED speakers and a behind the scenes look with our producers. A Plus subscription also lets you listen to regular episodes (like this one!) without sponsors. Sign-up at: plus.npr.org/ted See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

This is the TED Radio Hour. Each week, groundbreaking TED Talks. Our job now is to dream big. Delivered at TED conferences. To bring about the future we want to see. Around the world. To understand who we are. From those talks, we bring you speakers and ideas that will surprise you.

You just don't know what you're going to find. Challenge you. We truly have to ask ourselves, like, why is it noteworthy? And even change you. I literally feel like I'm a different person. Yes. Do you feel that way? Ideas worth spreading.

From TED and NPR. I'm Anush Zummerody. And on the show today, the brain, and how it changes at every stage of life. Starting on day one. Yeah, sleepy head, wake up. Because from the moment we're born, the world around us begins to shape how our brain works. So, you have makeup. Yeah.

Within the first few days and weeks of a baby's life, she learns to recognize her parents to coo and smile. Another few months, and she'll giggle. Show off new motor skills. Can you put up your stomach? You can do, my love. And start babbling to communicate, prompting us grown-ups to babble back. Soon little ones pick up words with real meaning. Say duck.

Say book. Book. Can you say ball? Can you say dadda? And every day they understand more about the world around them. Show me your elephant, Mabel. Do you want to do it? Can Cooper have a turn? No, I'll have a turn.

And they'll work to build skills they'll use their whole lives. Sometimes means singing along to the same song every single day. All this is to say, there is a lot happening in a child's brain during those first few years. We're born with 100 billion neurons or brain cells, and every minute in the first few months of life, we generate between 250,000 and 500,000 new brain cells or neurons every minute. This is Kimberly Noble. She's a professor of neuroscience at Columbia University. But it turns out that most of our brain growth early in life isn't actually the development of new brain cells, but the connections between cells.

If you look at it under a microscope, we don't see that many connections between brain cells when we're born. But by the time we're three years old, we have a thousand trillion connections between our cells. And we know that early experience really really. helps to shape that synaptic developmental process. People have said that the human brain is the most complex three pounds in the universe. And I love that saying because it really sort of gets to the amazing complexity that happens with all of us in the first few years of life. During each stage of our life, our brain morphs and changes from those first moments through our cringy teens, well-past adulthood, midlife, and into our senior years.

Our experiences shape how our brain develops, but so do our genetics, hormones, and even what we eat. And so today on the show, ideas about the brain at every stage of life, how it changes from childhood into old age, and the pivotal moments when a mind can either flourish or decline. Kimberly Noble's focus is on early childhood, because those first firsts, few years, even before kids go to school, are really important for brain development. And she's wondering why some kids get to kindergarten and are able to hit every cognitive and developmental milestone while others struggle. We know that by the start of school, we already see dramatic differences in what we call

early school readiness skills, early literacy and early math. And those differences tend to persist across most schooling. So the gap doesn't ever really narrow and in some cases may widen, which, of course, leads to differences in high school achievement, high school graduation rates, college attendance rates,

and ultimately employment. Here's Kimberly Noble on the TED stage. I'm about to share with you are findings from a study of the brains of more than 1,000 children and adolescents. Now, these were children who were recruited from diverse homes around the United States,

and this picture is an average of all of their brains. Now, one of the things we were very interested in was the surface area of the cerebral cortex, or the thin, wrinkly layer on the outer surface of the brain that does most of the cognitive heavy lifting. And that's because, past work by other scientists has suggested that in many cases, a larger cortical surface area

is often associated with higher intelligence. Now, in this study, we found one factor that was associated with the cortical surface area across nearly the entire surface of the brain. That factor was family income. Family income. The study looked at families with incomes ranging from $20,000 a year to $200,000 a year. And they found that families with more resources tend to have an advantage. There's less stress in the household, more time to interact,

and access to more nutritious food. And on average, higher income meant increases in brain surface area and higher cognition. It's also very important to keep in mind that, you know, while we can say that on average in this sample of more than 1,000 children and teens, on average higher family income was associated with larger brain surfaces, that's just an average. So there were plenty of children from higher income homes with smaller brain surfaces and plenty of children from lower income homes with larger brain surfaces. So in no way could I know an individual child's family income and predict with any accuracy what that particular child's brain surface would look like. Right. But what you can say is that the chances are that if you lived in a higher income family, the chances are that that that surface of the brain,

would be bigger and you would have a higher aptitude. That's right. That's right. And the relationship between income and children's brain structure was actually steepest at the low end of the income distribution. So an extra $10,000 a year for a family earning $100,000 a year would certainly be nice, but probably wouldn't have a dramatic effect on their day-to-day lives. Whereas an extra $10,000 for a family only earning $20,000 a year would likely make a pretty remarkable difference in their day-to-day lives. I want you to imagine for a moment, two children. One is a young child born into poverty in America.

The other is also an American child, but one who was born into more fortunate circumstances. Now, at birth, we find absolutely no differences in how their brains work. But by the time those two kids are ready to start kindergarten, we know that the child living in poverty is, likely to have cognitive scores that are on average 60% lower than those of the other child. Later on, that child living in poverty

will be five times more likely to drop out of high school, and if she does graduate high school, she'll be less likely to earn a college degree. By the time those two kids are 35 years old, if the first child spent her entire childhood living in poverty, she is up to 75 times more likely to be poor herself. Okay, again, these are averages, and there are lots of factors at play here. For example, the systemic racism that makes it three times as likely that black and Hispanic children will grow up in poverty compared to white children in the U.S.

But Kimberly is strictly looking at the effects of income on brain development. And when she controlled for race, gender, and genetic ancestry... We didn't find any what we would call statistical interaction between income and gender. or income and race, meaning that this effective income was consistent, whether the child was a boy or a girl, and regardless of their racial background. And so what's happening in these families that plays such a big role in the developing brains of their children? So we think that there are likely a lot of mechanisms and pathways that sort of account for those links between family income and children's outcomes. You know, one thing we've been very interested in is differences in family stress. So we know from a great deal of research in both animals and humans that there are certain areas of the brain that are particularly sensitive to the experience of stress.

And so we reason that since we see socioeconomic differences in those regions, they may be partially accounted for by differences in the experience of stress across families. We have recently started measuring stress not just in terms of the perception of stress, but, also in terms of stress physiology by taking small samples of hair, which can then tell us about the average levels of cortisol stress hormone for the last several months. And on average, more advantaged parents tend to have lower levels of hair cortisol, supporting this idea that the biology of stress really might account for socioeconomic differences in brain development in kids. And stress for parents could present itself in lots of ways, like access to health care or nutritious food or hourly jobs where you can't leave to go pick up your

kid or go to a doctor's appointment. Like stress compounds in many, many ways when money is tight, right? Absolutely. So there are lots of different experiences that contribute to stress and lots of different ways to measure stress. Right. So we try to get at numerous different facets of stress in the measures that we include. But it doesn't have to be that way. As a neuroscientist, one of the things I find most exciting about the human brain is that our experiences change our brains.

Now, this concept, known as neuroplasticity, means that these differences in children's brain structure don't doom a child to a life of low achievement. The brain is not destiny. And if a child's brain can be changed, than anything is possible. So let's consider first intervening at the level of learning itself, most commonly through school-based initiatives.

Now, should we be encouraging teachers to focus on the kinds of skills that disadvantaged kids are most likely to struggle with? Of course. The importance of high-quality education based in scientific evidence really can't be overstated. And there are a number of examples of excellent interventions targeting things like literacy or self-regulation

that do, in fact, improve kids' cognitive development and their test scores. But as any intervention scientist doing this work would tell you, this work is challenging. It's hard to implement high-quality evidence-based education. And in many cases, these disparities in child development emerge early well before the start of formal schooling. Sometimes when kids are just toddlers.

And so I would argue school is very important. But if we're focusing all of our policy efforts on formal schooling, we're probably starting too late. So if it's too late by the time kids get to kindergarten, how can we as a society make sure every child's basic needs are met? When we come back, Kimberly Noble shares one big idea. On the show today, ideas about the brain at all stages of life. I'm Manushe Zamoroti, and you're listening to the TED Radio Hour from NPR. Hey, it's Manush, and we are in the midst of a six-part special series called,

called Body Electric. It's an interactive investigation into the relationship between our technology and our bodies and how we can make it better. We don't remember a time before this kind of stress on the body. On episode two, a history of the personal computer told from the perspective of our anatomy. I think a lot of us don't realize how much pain we live in because of our interactions with computing. The extended sitting, the use of the key.

board, which causes all sorts of strain in the wrists, the hands, the fingers, the elbows. There's the posture of sitting, which has a whole connection of things that can do between the back, the shoulders, the neck, as well as like the hips, depending on the chair. And then you're also maintaining a very specific head posture by looking at the screen. NPR's Body Electric. Listen to the first two episodes in the TED Radio Hour feed right here, right now. It's the TED Radio Hour from NPR. I'm Anoush Zamorodi.

On the show today, life stages of the brain. And we were just talking to neuroscientist Kimberly Noble, who says that a huge factor in the way a child's brain develops is family income, with the biggest difference for kids living under the poverty line. What about taking a step back and focusing on trying to change children's experiences? What particular experiences are associated with growing up in poverty

and might be able to be targeted to promote brain development and learning outcomes for kids. Of course, there are many, right? Nutrition, access to health care, exposure to secondhand smoke or lead, experience of stress or discrimination, to name a few. In my laboratory, we're particularly focused on a few types of experiences

that we believe may be able to be targeted to promote children's brain development and ultimately improve their learning outcomes. So I want to share an idea with you. What if we tried to help young children in poverty by simply giving their families more money? We've known for decades from work by social scientists and others that growing up in poverty puts kids at risk for a host of negative outcomes in terms of their cognitive development, their social emotional development, their brain development, their mental and physical health.

However, there are many people who would say, well, poverty isn't the cause of those. problems. It's all of the things that are associated with poverty that are really driving those effects. And from a scientific perspective, the only real way to answer that is through the gold standard of scientific study designs, which is a randomized controlled trial. Which is what you did, right? In 2018, you started the baby's first year's study and recruited about a thousand low-income mothers to participate after they gave birth, right? Right. And upon enrolling in the study, all mothers began receiving an unconditional monthly cash gift every month for the first 40 months of their children's lives, so till just after their children turned three. But we randomized the moms to either receive a large monthly cash gift of $33 a month or a nominal monthly cash gift of $20 a month. And that difference has been shown in the social science literature to be associated. with improvements in children's academic achievement, improved time, more time spent in the labor

force when children grow up, and even better health when children grow up. But again, the past work was really looking at correlational findings, so associations between higher income and children's outcomes, but they didn't rely on causal evidence. So here we're able to actually examine what's the causal impact of poverty reduction. on children's cognitive, emotional, and brain development in the first three years of life when we believe that the developing brain is most malleable to experience. Okay, but there are going to be some people who say, like, this sounds kind of simplistic, like you're throwing money at a problem.

But this trial, which we should say is the first of its kind, could actually have huge policy implications, right? I mean, you know, ideally we live in a more equitable society where the basic needs for a child's physical and emotional and cognitive health would be met from day one. But we don't. And so these findings could actually help us make policy to change that. Yeah, you know, it's an interesting question. So, you know, I do think to the extent that neuroscience can help in convincing people about these very real needs,

then, you know, I'm all for it. I also think it's important to think about shifting the conversation or shifting the spotlight onto children, right? So much of the intergenerational cycle of poverty has often been attributed to, you know, whether individuals are willing to pull themselves up from their bootstraps. But babies don't have bootstraps. And so when we think about that, right, so if we're shifting the spotlight onto children who we all agree, it's not up to them. if they're provided with resources or not. But if we take a step back even further and address income disparities themselves,

you know, empower families to spend money on things that they actually need to support their own family's well-being, it's suddenly a very different conversation. Now, we won't have definitive results from this study for several years. And if nothing else, a thousand newborns and their moms will have a bit more cash each month

that they tell us they very much need. But what is the same? if it turns out that a cost-effective way to help young children in poverty is to simply give their moms more money. If our hypotheses are borne out, it's our hope that results from this work will inform debates about social services that have the potential to affect millions of families with young children.

Because while income may not be the only or even the most important factor in determining children's brain development, it may be one that, from a policy perspective, can be easily addressed. Put simply, if we can show that reducing poverty changes how children's brains develop and that leads to meaningful policy changes, then a young child born into poverty today

may have a much better shot at a brighter future. Thank you. That's Kimberly Noble. She's a professor of neuroscience at Columbia University. You can find her full talk at TED.com. On the show today, ideas on healthy brain development at every stage of life, including the next stage, adolescence. I am the parent of two kids who are just on the cusp of being teenagers, and I am slightly terrified. In my mind, I have this constant reel of stereotypes pulled from all the teen movies that I grew up watching.

Eat my shorts. I feel almost programmed to think, The teens are selfish. About the audition, you're ruining my life. Dramatic. Marsha, Marsha. Hormonal. It was more than love, and it wasn't just some stupid feeling.

Impulsive. In one time, at band camp? Just kind of dumb. How old are you? Old enough to kick your butt through your skull and splatter your brains on the wall? Yeah, he's a juvenile. But on the other hand, I know that's not fair. It's absolutely not fair.

I think adolescents get a really bad rap. This is Adriana. Galvan. And I am a professor of psychology at UCLA. Specifically, Adriana studies the science behind the ever-changing adolescent brain. And adolescents are actually an awesome set of people who are in this wonderful time in life when they are naturally inclined to explore and to try new things and to meet new friends and sometimes maybe gets them into trouble. But for the most part, Most of us get through adolescence relatively unscathed, and we emerge as more confident, self-assured people

who are interested in the world. Hi, thank you. I love your enthusiasm. This is Adriana on the TED stage. She says that normalizing the sometimes seemingly abnormal but actually very normal teenage brain is important, so important that she gave a TED talk about it to teenagers. How does the teenage brain make decisions?

One of the first discoveries relevant to this topic was made when we discovered that the part of your brain in the very front called the prefrontal cortex, which is the last brain region to develop because your brain develops from the back to the front, continues to change up until the mid-20s. And the reason this is relevant is because the prefrontal cortex is a part of your brain that helps you think about the consequences or potential consequences of your actions before you do them. It helps you regulate your behavior and your emotions. And so it makes sense that if this part of the brain isn't fully available into well-past adolescence, then teenagers may make more impulsive decisions with less regard for the potential future consequences. But we now know that the story is far more interesting and complicated than that. And in fact, what we really need to do is think about how brain regions that are not at the

surface of your brain, but in the deeper layers, how they change. In one region we focus on is called the striatum. And the striatum is the key component of the reward system. So when you receive something that you find rewarding, your striatum is very responsive, and it releases something called dopamine. So in my lab, we study this reward system. In her lab, Adriana does all kinds of research to understand this reward system. Like using fMRI machines to study the brains of kids, adults, and teens, specifically looking at the striatum to see what they find rewarding. And what's something that people find rewarding?

Sugar. We hooked them up to a straw and we fed them spurts of sugar water every so often. And you can see that everybody liked it. Kids liked it, adults liked it, but teens really liked it. It's a teenage brain that was going crazy. It was really excited to get it. It's not just that they liked it more. They craved it more.

So this is telling us that there's something really special about the teenage brain. There's a sharp increase in sensitivity to rewards and novel information from childhood to adolescence, but then there's a sharp decrease from adolescence to adulthood. And that probably has something to do with the fact that the prefrontal cortex, is starting to come online as people transition into adulthood and regulating the emotional response to rewarding information. So Adriana understood that teenagers' brains respond more to rewards, but how does that affect their decision-making?

For example, if we want to test how the adolescent brain responds when they're taking a risk, we try to mimic and present them with a virtual environment where they're asked to take risks. Adolescents are on a racetrack, simulated of course, and they're told that they have to get to the end as quickly as possible to earn some extra money. And they'll come to a stoplight. Oh, no. Well, what we find is that adolescents compared to adults are more likely to run the yellow light. So that's our measure of risk.

They're simply more active in their reward system. And that tells us that given the very same exact conditions, the adolescent brain is perceiving that risk differently. And not only is the brain proceeding it differently, but it actually leads to a difference in their behavior that we can observe, that we can measure. Okay, so adolescents were willing to take bigger risks to get the reward. But how do consequences fit into all of this done? Well, it's not that they don't understand that they could get in trouble for sneaking out at night or that they could get in. trouble for running the light, but that the rewards of that are much more powerful. And if we think about how those rewards happen or the context in which those rewards or risks occur, it's typically

when they're hanging out with their friends. Very few teenagers take risks alone. And because there's a thrill to being with your friends, making your friends laugh, for being the hero, for kind of being defiant or doing something that adults don't want you to do. And that too is a part of the of establishing independence. It's kind of saying to adults, yeah, I know it's wrong, but you know what, I want to do it anyway. And for adults, we say, well, that's such a stupid decision. That's a risk that could have killed someone. You could have really gotten in trouble. You could have jeopardized your standing in school or something like that. But for adolescents, the real risk is not fitting in. The real risk is not getting that social capital. And so maybe it's actually a very rational

decision to sneak out of the house if that's going to get you some bonding experience. I'm not suggesting teenagers should do it. But I'm just saying that the calculation is different for adolescents than for adults. So what you ultimately are arguing in your talk is that while risky behavior can be dangerous, it's actually really necessary for teens to learn and to grow. Yeah. This same, this reward system that I'm talking about is also what responds to. novelty. And that's what it,

adolescence is all about novelty, right? Because you've already gotten the basics down. You know how to walk. You know how to talk. You know how to bond to your caregivers. But what's new is that you're learning new things in school. You're being exposed to poets. You are learning calculus. You are also learning about love. You're having your first crush. You're starting to think about college and your life and your identity separate from your caregivers. And all of that is super exciting.

And it's no coincidence that our brains have evolved in a way to have this period in life when novelty is super exciting. Yeah, and I guess there's now an opportunity for this kind of pure passion to be expressed. I mean, thanks to the world we live in now with social media. Like, just thinking over the past few years, young people have become so influential, like Malala Yousafzai and Greta Tunberg and more recently the poet Amanda Gorman. Yeah. And I wonder, like, do you feel kind of triumphant that now teens can truly be fearless publicly and express themselves in new ways? Absolutely. I'm so excited that you said that because so many wonderful things about adolescents that they mobilize, that they're energetic, that they're really passionate about causes they believe in, but they're able to influence other people to think pro-socialally about how they can make the world a better place. And because they don't have the experience or the cynicism that maybe sets in as we get older, they are fearless. And that's part of what makes adolescents adolescents, that they're fearless, passionate, and want to influence other people.

They want to connect with other people and things they care about. And social media has given them that opportunity to do so. That's Adriana Galvan. She's a neuroscience professor and dean of undergraduate education. at UCLA. You can see her full talk at ted.npr.org. Okay, so quick recap,

every minute babies develop up to 500,000 neurons and the brain continues to grow and transform all the way through adolescence until about the age of 26. Beyond that, people used to believe that the adult brain

stopped growing new neurons. But that's not the case. Yeah, yeah, of course, yeah, yeah. I mean, on average, would produce 700 new neurons per day. This is neuroscientist Sandrine Turey. We all agree that this is a very small number. You know, you don't need a lot of these new neurons

because it's part of a network. You don't need a lot to disturb the whole network. So I think that although this is a small number, but it doesn't prevent them from having very specific functions, let's say, or important functions. Sandrine studies neurogenesis, the process of creating new neurons. And when you are very young, so let's say, you know, until four years old, you have a lot of neurogenesis going on. You would have a burst of neurogenesis, but it goes down as you age.

And that continues well into the 90s. So there is something that is happening, but it's not everywhere in the brain. For adults, that growth is happening in one area of the brain, the hippocampus. So the hippocampus is really a hub that's going to have multiple role. I mean, most people will think that, yeah, this is for memory. And it's right. It is for memory formation, but it's also important for mood and emotion. So indeed, in the hippocampus, you still keep adding neurons that are important for your mental health in general, like cognition and, you know, mood.

And this is something that you can try to control to some extent without stressing yourself too much. Can we just pause here and say, like, what a relief it is to know that there is neural activity, neural growth in the adult brain? But it does sound like you're saying, you know, it's not just the way the brain works. It's that we actually can do something about it too. So, yeah, well, exactly. I mean, like, what if you are aware of it, right? What do you do about it now? Because it's a very sensitive phenomenon that you can increase it or decrease it

super quickly with a lot of intervention that you do every day. In just a minute, neuroscientist Sandrine Toure on what we adults can do to promote our neurogenesis and help our brains be healthier. On the show today, healthy brain development at every stage of our own. life. I'm Manoosh Zamorodi and you're listening to The TED Radio Hour from NPR. Stay with us. It's the TED Radio Hour from NPR. I'm Anoush Zamorodi. Today on the show, how our brains change through every stage of life. We were just hearing neuroscientist Sondrine Touret, explain the process of neurogenesis, our brain's ability to create new neurons. And even though adults won't grow as many neurons as

kids or teenagers, our daily choices can help. Can we control neurogenesis? The answer is yes. And we are going to do now a little quiz. So I'm going to give you a set of behavior and activity. And you tell me if you think they will increase neurogenesis or if they will decrease neurogenesis. This is Sandrine Touret on the TED stage.

During this quiz, she went through six ways that we adults can promote our brain health. So what about learning? Increasing? Yes. So learning will increase the production of these new neurons. So we know that learning itself will increase neurogenesis. So learning, you know, a new language, of course, why not? But, you know, the hippocampus is one of the center for spatial recognition. So maybe not exercising always the same route. You know, if you go outside for a walk or for a run, maybe taking a new way or maybe even. taking away you don't know yet. Okay, so let's move to the second one, which was stress. So yeah, stress, well, this, you know, chronic stress, that's really bad for neurogenesis. And I know at the moment it's very difficult to do anything against, you know, stress.

But this is really detrimental for neurogenesis. So having positive action lack learning. You know, this is how you maybe could counteract some of the detrimental effect of the stress. Okay, so sleep deprivation was the next one. This makes sense to me. Yeah. Yeah. So it's quite intuitive indeed. You know, when you are sleep deprived, you know, you cannot think straight. But it's over time if you are going to look at this chronic sleep deprivation that would be negative. How about sex?

Oh, wow. Yes, you're right. It will increase the production of new neurons. However, it's all about balance here. We don't want to fall in a situation. About too much sex leading to sleep deprivation. This one got a laugh from the audience. Yeah, intercourse.

Yes, yes. So, yeah, so that's a good one to keep in mind indeed. And finally, diet and exercise. How about running? So I will let you judge that one by yourself. So activity impact on neurogenesis. But that's not all. What you eat will have an effect on the production of new neuron in the hippocampus.

So, calorie restriction of 20 to 30% will increase neurogenesis. Interminant fasting, so spacing the time between your meal, will increase neurogenesis. Intake of flavonoid, which is contained in dark chocolate or blueberry, will increase neurogenesis. Omega-free fatty acid present in fatty fish like salmant will increase the production of these new neurons. Conversely, a diet rich in high-saturated fat will have a negative. impact on neurogenesis. Ethanol, intake of alcohol, will decrease neurogenesis. However, not everything is lost.

Resveratrol, which is contained in red wine, has been shown to promote the survival of these new neurons. So next time you're at a dinner party, you might want to reach for this possibly neurogenesis neutral drink. So, you know, I do understand that research has not definitively shown that these things promote neurogenesis. But listening to you, part of me wants to fast and only eat salmon, blueberries and dark chocolate and run six miles a day and make sure I get nine hours of sleep every night.

Because it makes me think, like, wow, I might have some control over my body, but also like, Sandrine, we are only human and it's just not possible to do all these things. So I guess I'm wondering, like, what is the biggest single piece of advice you have for us on how to make sure our brains stay healthy. Yeah, so I think people will have to find their own balance because if you are pushing yourself too hard, then this is another form of stress, right? So you want to do something that feels good to you, right? But yeah, people have to find what works for them.

I think because otherwise, if you have to force yourself, then it's counterproductive because it's going to be a stress. You know, I'm at that age where I'm starting to, I'm in my late 40s. I'm starting to think about the next phase. I'm not there yet, but is there some way to sort of prepare myself for the senior years, as it were? I don't know. Yeah, right? That's a big question, isn't it?

Yeah, that's a really good question. I'm sure you can. I'm sure we can all do our best, you know, from the data we have. It does show that what you do in your younger year will have an impact, you know, on the long term. So I think you can prepare now, indeed, and hoping for the best. Like I do. That's neuroscientist Sandrine Touret. She leads the adult neurogenesis and mental health laboratory at King's College, London.

You can check out her full talk at ted.com. On the show today, how our brains change throughout our lives. And now, finally, on to the aging brain. And for women, a stage in life. that most people associate with changes in the body rather than brain function. Menopause. We associate menopause with the ovaries. But when women say that they're having hot flashes, night sweats, insomnia, memory lapses, depression, anxiety, those symptoms don't start in the ovaries.

They start in the brain. This is neuroscientist Lisa Mascone on the TED stage. Those are neurological symptoms. We're just not used to thinking about that. as such. So just to clarify, this is you. You are not crazy. Not crazy, because women's brains age differently than men. And Lisa's research is just beginning to shed light on how and why that is. And this is really important because the way the brain ages is really in big part dependent on the health of the reproductive system in women. And the reason for that is that their hormones play a big role

brain function. And this is a connection that's been really overlooked systematically for decades. Probably centuries, really. And we should just mention that when we say women, we're referring to those born in bodies with ovaries. And as we've talked about on the show before, there are a lot of people that don't fit into that description. Yes. And so in your TED Talk, you say that the brain and the ovaries are connected. Like, it's like they're talking to each other all the time, right? Right. Yes, yes, they do from the moment we're born. So the brain is connected to the reproductive systems via a network that is called the HPG axis, which is hypothalamus pituitary gonadal axis,

which, yeah, which is a very important system that connects specific parts of the brain, like the hypothalamus, which is, for example, is in charge of regulating body temperature, but also is in charge of making hormones like estrogen and progesterine. And then there's the pituitary gland, which is in charge of making other hormones. And all these hormones together are responsible for the menstrual cycle in women. And they are connected to the ovaries, the conundal system. Men have more testosterone. Women have more estrogens.

But what really matters here is that these hormones differ in their longevity. men's testosterone doesn't run out until late in life, which is a slow and pretty much symptom-free process. Of course. Women's... Right? Women's estrogens, on the other hand, start fading in midlife during menopause,

which is anything but symptom-free. So when women say they're having half-lashes, right? That's the most common symptom of menopause. They're having nice sweats or depression, anxiety, brain fog, it's a very common symptom, memory lapses, those symptoms don't start in the ovaries, they start in the brain. And what we have shown is that the symptoms are very likely caused by energy changes inside the brain. So the health of the ovaries is linked to the health of the brain and the other way around. At the same time, hormones like estrogen are not only

involved in reproduction, but also in brain function. And estrogen in particular, or estradiol, is really key for energy production in the brain. At the cellular level, estrogen literally pushes neurons to burn glucose to make energy. If your estrogen is high, your brain energy is high. When your estrogen declines, though, your neurons start slowing down and age faster. For women, brain energy is usually fine before men or hormones. but then it gradually declines during the transition. And this was found independent of age.

It didn't matter if the women were 40, 50 or 60. What mattered most was that they were in menopause. So Lisa, you're doing more research into this, but basically are you finding that women's brains are more sensitive to hormone changes as we age? Well, from my perspective, it means that the role of your hormones is a little bit stronger in your brain. If you're female. Yes, if you're a female, because you're already wired to go through not just puberty, but also there's an expectation that you're going to be pregnant to have kids and then eventually lose your fertility and survive it. So I think there's more, and this is speculative, but I think there's more that needs to happen in a woman's body.

So this is the brain anatomy or menopause, if you will. When estrogen doesn't activate the hypothalamus correctly, the brain cannot regulate body temperature correctly. So those hot flashes that women get, that's the hypothalamus. Then there's the brainstem in charge of sleep and wake. When estrogen doesn't activate the brainstem correctly, we have trouble sleeping. Or is the amygdala, the emotional center of the brain,

close to the hippocampus, the memory center of the brain. When estrogen levels eb in these regions, we start getting mood swings, perhaps, they'll forget things. See, I think it's really important to appreciate that for women, there's a very different story going on, and we should be more focused on the health of our hormones and really protecting our hormones, because they have really strong effects on their brains.

Is that similar to why I have hypothyroidism or Hashimoto's, a thyroid disorder? And when I was diagnosed with that, it was like, oh, this happens to a lot of women. Yes, this is one of the things that we're looking into right now. We know that menopause acts a little bit like a trigger for existing medical predispositions. If you have a hormonal problem to start with, like thyroid issues, does it really like. to become an actual problem during menopause. Anxiety. There's a good chance that you're going to get more after in menopause.

I'm sorry. But it's true. You know, the thing is that we don't talk about it. No. I specialize in Alzheimer's prevention. The reason being that I have a family history of Alzheimer's that runs in my family and really affects the women in my family pretty heavily. And Alzheimer's disease actually affects more women than men.

So currently in the United States, of every three Alzheimer's patients, two are women. Wow. Which really means that for every man suffering from Alzheimer's, there are two women. Alzheimer's disease starts with negative changes in the brain, years, if not decades, prior to clinical symptoms. And my work in particular has shown that Alzheimer's disease starts earlier in women's brains than men's brains, specifically in midlife and even more specifically during the transition to menopause. I've never heard that actually. I find it's so bizarre that this is not common knowledge and it's not something your doctors

warn you about. And society is just absolutely unprepared. And doctors mostly are unprepared to really help women during this inevitable part of life. Like all these symptoms that women have, in my opinion, could be avoided. How? Oh, by, living a certain lifestyle or taking certain medications or taking certain precautions. Food, for example. Studies have shown that the Mediterranean diet in particular is supportive of women's help. Women on this diet have a much lower risk of cognitive of cognitive decline, of depression, of heart disease, of stroke, end of cancer, and they also have fewer hot flashes. What's interesting about this diet is that it's quite rich in foods that contain estrogens

in the form of phytocetrogens, or estrogens from plants that act like mild estrogens in our bodies, especially from flax seeds, sesame seeds, dried apricots, legumes, and the number of fruits. And for some good news, dark chocolate contains phytoestrogens too. So diet is one way to gain estrogen. but it's just as important to avoid things to suppress our estrogens instead, especially stress. Stress can literally steal your estrogens, and that's because cortisol, which is the main stress hormone, works in balance with our estrogens. So if cortisol goes up, your estrogens go down.

Your cortisol goes down, your estrogens go back up. So reducing stress is really important. It doesn't just help your day, it also helps your brain. So these are just a few things that we can do to support our brains and there are more. But the important thing here is that changing the way we understand the female brain really changes the way that we care for it. Lisa, we have gone from talking about baby's brains to adolescent brains to adult brains. And now we are talking about what happens in women's brains as they go through menopause and transition into this sort of last stage. in their lives as seniors.

And I guess, you know, we have spanned all that time, but I'm wondering in the next five, 10 years, what are you hoping to discover with your research? Like, what is the question that you want to answer or understand about our aging brains? Well, I think there's so much that really needs to be done. And I work in the medical field. And still today, women's brain health is one of the most under-researched, under-diagnosed, and under-treated fields of medicine. Even though women have twice the risk of anxiety and depression as men,

we're three times more likely to have an autoimmune disorder, including those that attack the brain, like multiple sclerosis. We're four times more likely to have headaches and migraines. We're much more likely to develop a brain tumor like a meningioma. We're far more likely to die of a stroke when we get a stroke. And we're also more likely to get Alzheimer's disease, which is the most common form of dementia on the planet. planet and really a major public health issue.

And if we don't understand her women's brains work, we will not be able to really help them. That's neuroscientist Lisa Moscone. Her latest book is the XXBrain. You can see her full talk at TED.com. And you can also hear her talking about hormones and biological sex on our episode, The Biology of Sex. Thank you so much for listening to our show this week on brain stages. To learn more about the people who were on it, go to ted.npr.org. To see hundreds

more TED Talks, check out TED.com or the TED app. And if you've been enjoying the show, we would be so grateful if you left a review on Apple Podcasts. It's the best way for us to reach new listeners. So thank you. Our TED Radio production staff at NPR includes Jeff Rogers, Sanaz-Meshkampur, Rachel Faulkner, Diba Motisham, James Delahoussi, Jacey, J. Howard, Katie Montalione, Maria Paz Gutierrez, Christina Kala, Matthew Cloutier, and Farah Safari, with help from Daniel Shukin. Our intern is Janet Ujongli. Our theme music was written by Ramteen Arableu.

Our partners at TED are Chris Anderson, Colin Helms, Anna Fulin, and Michelle Quint. I'm Manus Shumeroody, and you've been listening to the TED Radio Hour from NPR.